Chemistry Chapter 4 Flashcards

Mixtures and Solutions

• Homogeneous mixtures: Evenly blended combinations of two or more substances in solid, liquid, or gas form.
• Solvent: The medium that dissolves a solute in a solution.
• Solute: The substance that is dissolved in a solution.
• Electrolytes: Substances (e.g., NaCl) whose aqueous solutions contain ions and can conduct electricity.
• Nonelectrolytes: Substances that do not ionize in water and cannot conduct electricity, exemplified by sugar (C₂H₂₂O₁₁).
• Dissolution: The process of breaking up or dissolving a substance into parts.

Ions and Acids

• Cations: Positively charged ions.
• Anions: Negatively charged ions.
• Acids: Compounds that produce hydrogen ions when dissolved in water; they are sour, dissolve metals, and conduct electricity.
• Strong electrolytes: Compounds that dissociate completely into ions in solution (e.g., HCl).
• Weak electrolytes: Compounds that partially dissociate into ions (e.g., acetic acid).

Chemical Reactions

• Chemical equilibrium: A state where the rates of forward and reverse reactions are equal, leading to no net change in reactants and products.
• Precipitation reactions: Reactions between ionic compounds that produce an insoluble solid upon mixing.
• Precipitate: A solid formed from a solution during a chemical reaction.
• Net ionic equations: Only include the ions and compounds that undergo a change during the reaction while excluding spectator ions.

Solubility Rules

• Soluble ionic compounds: Strong electrolytes that dissolve well in water.
• Exceptions in solubility: Most carbonates are insoluble, except those with alkali metals and ammonium; sulfates of Pb²⁺ are also exceptions.
• Solvation: The process of surrounding solute ions with solvent molecules to form a solution.

Titration and Molarity

• Molarity: The concentration of a solution expressed as moles of solute per liter of solution.
• Dilution: The process of reducing solute concentration by adding solvent without changing the amount of solute.
• Titration: The method of determining the concentration of an unknown solution by reacting it with a solution of known concentration until complete reaction (equivalence point).

Ionic Compounds and Reactions

• Metathesis reactions: Involve the exchange of component ions between reacting substances.
• Acid-base neutralization: H⁺ and OH⁻ ions combine to form water.
• Activity series: An ordered list of metals ranked by their reactivity.

Oxidation and Reduction

• Oxidation-reduction (redox) reactions: Involve the transfer of electrons between species; oxidation refers to the loss of electrons.
• Oxidation states: Denote the degree of oxidation of atoms; for elemental forms, the oxidation number is zero.
• Specific rules for oxidation states: Fluorine has -1, oxygen usually -2, hydrogen varies between +1 (with nonmetals) and -1 (with metals).

Practical Applications in Chemistry

• Steps for writing net ionic equations involve writing balanced molecular equations and identifying ions.
• Steps for converting moles to atoms/molecules include calculating moles and using Avogadro's number.
• To name ionic compounds, positive ions precede negative ions, with -ide added to non-polyatomic anions.

Memory Aids

• Mnemonic for alkanes: "My Enormous Penguin Bounces Pretty High" helps remember the series: Methane, Ethane, Propane, Butane, Pentane, Hexane.